WASHINGTON — The Nets, after last night’s 89-74 loss to the Wizards, are now 50 games into their season. And, even with more than 60 percent of play complete, the one thing the Nets are most consistent at is being inconsistent.

For a while, the reasoning was this was virtually a brand-new team, with nine new players and 12 who had played less than 20 games last season with the Nets.

But the time for that to be used as a valid reason for the seemingly endless string of peaks and valleys the Nets have gone through this season is quickly coming to an end.

“There’s only so long you can use that excuse,” said Deron Williams, who was one of the few Nets to play well, finishing with 20 points, six rebounds, five assists and two steals. “The thing is we have to find ways to play better.

“We’ve talked about energy and effort a lot this year, and that’s something that should be there. Especially with this team, we should always have effort. We’re a deep team, we have guys that can come in and fill the void if someone goes down … but there’s no reason why we should be talking about why the effort wasn’t there, why the energy wasn’t there, especially in some of these big games. Maybe this one wasn’t a big game for us, but it should have been.”

After the Nets’ bench combined to go 4-for-21 for 13 points in the game, interim coach P.J. Carlesimo made it clear the inconsistent performances could lead to some changes moving forward.

“We have people that are giving us good defense but they’re not giving us offense, or vice-versa, so we maybe have to look at the makeup of that second group and shake it up a little bit, because it is a concern,” he said. “It’s been a problem.”

Whether or not they considered it a big game, the Nets (29-21) simply couldn’t get out of first gear against the Wizards, particularly in a horrific second quarter when virtually nothing good happened for them. In a performance that ranked among their worst in a single quarter this season, they were outscored 30-11 after missing their first 12 shots in the quarter, and gave up an initial 19-2 run before Brook Lopez finally broke the scoring drought with a layup with 3:36 remaining.

The Nets finished the quarter 4-for-22 from the field, including 0-for-7 from 3-point range, and committed five turnovers, and ended the half down 51-31.

“Some of that’s Washington, but when you can’t make free throws, you can’t make 3-point shots and you can’t make shots in the paint, it’s very hard to win,” Carlesimo said. “I really liked our effort in the first and third, and for most of the fourth, but the second quarter was terrible.”

Even when Washington opened the door for a Nets comeback in the second half with a terrible showing in the third quarter, Carlesimo’s team couldn’t take advantage. Despite holding the Wizards to 6-for-18 shooting, the Nets shot just 41 percent from the field and went 7-for-14 from the foul line, ending the quarter down 12 and failing to get closer than 11 in the fourth.

Each member of the team has put forth spotty efforts, something Williams didn’t expect with a veteran team.

“We’re just so inconsistent,” Williams said. “Individually, I’ve been inconsistent, but as a team we’ve been inconsistent. There’s been too many ups and downs.

“We win five in a row, and then we hit these lulls. We win eight in a row, and then … there’s been a lot of bad habits. We start pointing the finger and getting a little selfish. … We’ve got to get out of that habit.”